Question

由于java HttpServer 的问题，我发疯了。我使用上下文等创建服务器，然后从客户端应用程序使用 URLConnection 和 InputStream 连接到服务器。

问题是，当客户端执行更多后续请求彼此过于接近时，客户端会经常（没有明显的逻辑）获取读取超时。为了避免这种情况，我必须从连接和下一个连接中放置 sleep（5000）（为什么5000？因为5000以下它仍然会超时）。

我已经尝试使用Executors（包含 Executors.newCachedThreadPool（）和 Executors.newFixedThreadPool（10），但没有。

使用2个客户端的另一个奇怪的事情：

客户1：第一个请求= ok
客户2：第一次请求=确定
等待少量秒数
客户1：第二次请求=确定
客户端1：第三个请求=冻结，它继续尝试（参见下面的代码），然后给出超时
客户端2：第二个请求= ok（客户端1仍在尝试并且超时）

所以..问题似乎与特定的客户端实例有关

这里有一些代码

服务器

try {
        cryptex = new ServerCryptex();
        final Executor multi = Executors.newCachedThreadPool();
        server = HttpServer.create(new InetSocketAddress(8888), 50);

        addContexts();

        server.setExecutor(multi);
        server.start();


    } catch (IOException ex) {
        Logger.getLogger(MyHttpServer.class.getName()).log(Level.SEVERE, null, ex);
    }

上下文添加了

server.createContext("/empty", new HttpHandler_Empty(this));

等

的客户端

这是执行请求的功能

 public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    URLConnection con = url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(7000);
    InputStream is = null;

    **NO PROBLEM UNTIL HERE**

    for (int i = 0; i < 5; i++) {
        try {
            System.out.println("open the stream, try #" + i);

            **TIMEOUT ON THE NEXT LINE**

            is = con.getInputStream();
            break;
        } catch (java.net.SocketTimeoutException ex) {

            **I THOUGHT TO USE THIS WAY TO TRY 5 TIMES THE CONNECTION BEFORE GIVING ERROR TO THE USER, BUT NOTHING. **

            sleep(500);
            if (i == 4) {
                throw ex;
            }
        }
    }
    String reply = readReply(is);
    System.out.println("read reply:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

真实代码（没有5次尝试代码）

public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    HttpURLConnection con = (HttpURLConnection) url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(2000);

    System.out.println("open the stream");
    InputStream is = con.getInputStream();

    String reply = readReply(is);
    System.out.println("risposta letta:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

错误

giu 12, 2018 10:58:01 PM gui.Client_GUI aggiornaUdg
GRAVE: null 
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1569)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
at net.ClientConnector.performRequest(ClientConnector.java:96)
at net.ClientConnector.checkKey(ClientConnector.java:43)
at net.Client.getUDG(Client.java:56)
at gui.Client_GUI.aggiornaUdg(Client_GUI.java:2407)
at gui.Client_GUI.jButton1ActionPerformed(Client_GUI.java:1917)
at gui.Client_GUI.access$000(Client_GUI.java:53)
at gui.Client_GUI$1.actionPerformed(Client_GUI.java:390)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

它可能是什么？你有什么建议可以避免这个问题吗？非常感谢您提前

Answer 1

我不知道问题的原因..但我决定使用Apache Java HTTP Client Library

这里是代码

public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);

    HttpClient client = HttpClientBuilder.create().build();
    HttpGet request = new HttpGet(url.toString());

    // add request header
    HttpResponse response = client.execute(request);

    System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

    String t = "";
    String s = rd.readLine();
    while (s != null) {
        t = t + s;
        s = rd.readLine();
    }

    System.out.println("risposta letta:" + t);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(t);
    } else {
        return t.getBytes();
    }
}

Java HttpServer读取超时，来自同一应用程序的后续请求彼此过于靠近

1 个答案: